Valve for rock drills



Jan. 12, 1943. w. A. MORRISON. 2,307,847

VALVE FUR ROCK DRILLS Filed Jan. 14, 1942 INVENTOR lgfamilMax-rwon.

I 5 ATTORNEY.

Patented Jan. 12, 1943 s'rrrs VALVE FOR ROCK DRILLS Application January 14, 1942, Serial No; 426,759

11 Claims.

This invention relates to rock drills, and more particularly to a distributing valve for a fluid actuated rock drill of the reciprocatory piston type.

One object of the invention is to obtain a lightweight valve capable of effecting a rapid distribution of th pressure fluid to the piston chamber.

Another object of the invention is to assure the introduction of a heavy charge of pressure fluid into the piston chamber with a minimum lift of the distributing valve.

Still another object is to prevent undue turbulence in the stream of pressure fluid flowing from supply to the piston chamber.

Other objects will be in part obvious and in part pointed out hereinafter.

rear and front ends, respectively, of the piston chamber.

Referring more particularly to the drawing, 23 designates, in general, the rock drill and 2| and 22 a cylinder and a back head that serve as casing parts for the rock drill and may be secured together in any suitable manner.

The cylinder 2! is bored to provide a piston chamber 23 having a free exhaust port 24 and containing a reciprocatory hammer piston 25 that controls the exhaust port 24. The piston 25 is shown as being of a well known type having a head 26 and a stem 21 that extends slidably through a washer 28 at the front end of the piston chamber 23 to form a closure therefor.

In the portion of the cylinder lying rearwardly of the piston chamber 23 is an enlarged bore 29 to accommodate valve and rotation mechanisms 30 and 3 I, respectively. The rotation mechanism lies in the outermost end of the bore 29 adjacent the back head 22 and comprises a ratchet ring 32 that is interposed between the back head 22 and the valve mechanism 30. Within the ratchet ring 32 lies the head 33 of a rifle bar 34 and in the head 33 are pawls 35 to engage the teeth 36 on the inner surface of the ratchet ring 32 for determining the direction of rotation of the rifle bar 34.

The rifle bar 3 extends axially through the valve mechanism 38 and is in fluted engagement with the piston 25, in a well known manner, to

prevent relative rotary movement between the rifle bar and the piston. A bearing is provided for the rifle bar 3d by a plate 31 interposed be-- tween the rotation mechanism and thevalve mechanism and having a bore 38 to accommodate the rifle bar. The rifle bar is additionally guided by a hollow extension, 39 on a plate 40 forming a rearmost part of the valve chest 41 of the Valve mechanism.

In addition to the plate 40 the valve chest 4! comprises plates 42, 33 and M, the latter being disposed at the front end of the bore 29 to serve as a bounding surface for the rearward end of the piston chamber 23. The plates 42 and 43 are interposed between and lie, respectively, adjacent the plates 48 and' M;

The plates 42 and d3 are suitably bored and the inner surfaces thereof cooperate with the peripheral surface of the extension 39 to define a valve chamber 45 of annular shape to accommodate a ring-shaped valve 43. The valve is guided by the extension 39 and the plates 42 and 44 and carries an external flange 41 that lies in an annular internal groove '38 in the plates 42 and 43.

On the front and rear surfaces of the flange d! are actuating surfaces 69 and 53, respectively, to which pressure fluid is conveyed for actuating the valve by kicker passages 55 and 52. The kicker passages extend through the valve chest and the cylinder and open into the piston chamber 23 at which point they are controlled by the piston 25. The kicker passage 5i leads from the forward end of the groove 48 to a point in the piston chamber forwardly of the free exhaust port 24, and the kicker passage 52 communicates the portion of the piston chamber rearwardly of the exhaust .port 2 3 with the rearward end of the be in constant communication with the source oi pressure fluid supply. Ports 5? and 58 in the wall of the throttle'valve and the cylinder 2!, respectively, afford communication between the passage I 56 and an annular groove 59 in the periphery of the ratchet ring 32 and said annular groove 59 communicates through passages 68, in the ratchet ring 32 and the plate 31, with a supply chamber 6| in the front end of the plate 31. V

The supply chamber 3171s of annular shape and communicates with the rear and front ends' of the valve chamber 45 through supply passages 62 and 63 in the valve chest, and in the wall of the valve 46 are passages 6 3 that are arranged in the same longitudinal planes as the outlet ends of the passages 62 and E3. Th passages 64 are in constant communication with both the supply passages 62 and 63 so that when the valve is in a position to uncover one group of supply passages, say those designated 63, pressure fluid will also issue from the passages 64 to assist in charging the piston chamber.

The pressure fluid issuing from the supply passages 62 and from the passages 64 in the valve passes through an inlet passage 65 leading from the rearward end of the valve chamber to the front end portion of the piston chamber 23, and pressure fluid flows from the supply passages 63 and the passages 64 through inlet passages 66 in the plate 44 into the rearward end of thepiston chamber 23 for driving the piston on its working stroke. The passages 66 lie outside of the plane of the passages 64 and open into an annular groove 61 in the front end of the valve 46.

In order to assure the prompt charging of the rearward end of the piston chamber with a low lift of the valve an additional inlet, in the form of a central port 68, is formed in the plat at to encircle the rifle bar 34. The port 68 lies inside of the plane of the passages 64 so that when the valve is unseated to charge the rearward end of the piston chamber the pressure fluid will flow outwardly and inwardly from the passages 63 and 64' to the passages 66 and the port 68 into the piston chamber.

As a preferred arrangement the valve 46 is provided at its front and rear ends with external annular shoulders 69 and 10, respectively, against which fluid medium compressed in the piston chamber by the piston may act to assist in throwing the valve.

In the form of the invention illustrated the ends of the valve serve as seating surfaces H to limit the travel of the valve and also as holdin surfaces against which pressure fluid flowing from the supply passages 62 and 63. and from the passages 64 acts to hold the valve 4% stationary during the charging of the ends of the piston chamber. The seating surfaces H seat alternately against seating surfaces 72 and F3, on the plates 44 and 46, respectively, encircling the outlet ends of the supply passages 62 and 63 and cooperate therewith to cut off the flow of pressure fluid from the supply passages to the inlet passages.

The operation of the device is as follows: With the valve 46 and the piston 25 in the positions shown in Figure 1, the rearward seating surface I! of the valve and the seating surface 13 will cooperate to seal the front inlet passage 65 from the supply passages. The front end of the valve will then be spaced from the seating surface 12,

and pressure fluid will flow from the supply passages 63 and the passages 64 both outwardly and inwardly through the space between the valve and. the seating surface 72, thence through the passages 66 and the port 88 into the rearward end of the piston chamber to drive the piston forwardly. The valve will be held immovable in the back end of the valve chamber by the pressure fluid acting against the front surface H of the valve.

As, the piston proceeds forwardly it will cover the free exhaust port 24. The air in the front end of the piston chamber compressed by. the

piston will then flow through the inlet passage.

and act against the shoulder is. This force is insuflicient, however, to overcome the force of the pressure fluid acting against the front end of the valve and the valve will, therefore, remain immovable. When the rearward end of the piston approaches the exhaust port 24 it uncovers the kicker passage 52 and pressure fiuid will then flow into the groove 58 against the actuating surface '50 of the valve and throw said valve forwardly, this force being, of course, augmented by the compression acting against the shoulder ill. The forward movement of the valve takes place immediately prior to the uncovering of the exhaust port 24 and no pressure fluid will, therefore, flow into the piston chamber without performing useful work.

The piston next uncovers the exhaust port 24 and the pressure fluid that served to drive it forwardly will pass to the atmosphere through the exhaust port 24 as will also that admitted into the rearward end of the groove 48 for driving the valve forwardly. This takes place at about the time the piston delivers its blow against the working implement which it is intended to actuate, the kicker passages being located in such wise with respect to the exhaust port that the actions of the valve and the piston will be nicely timed so that the subsequent admission of pressure fluid to the front end of the piston chamber will not lower the force of the working stroke of the hammer piston.

With the valve 26 in the new position the inlet passages leading to the rearward end of the piston chamber are cut off from pressure fluid supply by the seating surfaces H and 72. Pressure fluid will then flow from the supply passages 82 and the passages 64 through the inlet passage 65 into the front end of the piston chamber 23 to drive the piston 25 rearwardly. During this movement, the piston covers the exhaust port 24 and thereafter compress the air in the rearward end of the piston chamber and the channels leading to the shoulder 69 of the valve.

As the piston proceeds rearwardly it uncovers the kicker passage 51 and admits pressure fluid into the front end of the annular groove 48. Such pressure fluid acting against the actuating surface 49 augmented by the compression acting against the shoulder 69 will then return the valve to its initial position and cut off the further flow of pressure fluid into the front end of the piston chamber. Immediately after it uncovers the kicker passage 5! the piston will overrun the exhaust port 24 and the pressure fluid in the front ends of the piston chamber and the annular groove 48 will then exhaust to the atmosphere.

From the foregoing description it will be readily apparent to those skilled in the art that by connecting all of the supply passages alternately with the ends of the piston chamber the time required for charging the piston chamber will be greatly minimized and the valve may also be operated at a low lift. This is extremely desir able since it eliminates the chances of damage to the valve which may be operated at a fast rate of speed and be of light weight.

A further highly desirable advantage of the present invention is that by supplying pressure fluid into the space between the seating surfaces on the valve and the valve chest from opposed supply channels the objectionable turbulence usually occurring in the pressure fluid flowing from the valve to the piston chamber will be greatly minimized.

I claim:

1. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, means defining a valve chamber, supply passages in said means for supplying pressure fluid to opposed portions of the valve chamber, inlet passages leading from the valve chamber to the end portions of the piston chamber, and a valve in the valvechamber to alternately communicate the inlet passages with all of the supply passages.

2. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, means defining a valve chamber, opposed supply passages for pressure fluid opening into the valve chamber, inlet passages leading from the valve chamber to the piston chamber, and a valve in the valve chamber to control communication between the supply passages and the inlet passages and having a passage that constitutes a continuation of, one supply passage during the admission of pressure fluid to one end of the piston chamber and constitutes a continuation of another supply passage during the admission of pressure fluid to the other end of the piston chamber.

3. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid opening into the valve chamber, inlet passages leading from the valve chamber to the end portions of the piston chamber, and a valve to control communication between the supply passages and the inlet passages and acting to cutoff communication between the supply passages and an inlet passage leading to one end portion of the piston chamber and to simultaneously effect communication between all the supply passages and an inlet passage leading to the other end portion of the piston chamber.

4. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid opening into the end portions of the valve chamber, inlet passages leading from the end portions of the valve chamber to the end portions of the piston chamber, a valve in the valve chamber to control communication between the supply passages and the inlet passages and having a passage to alternately communicate the inlet passages with all of the supply passages during the admission of pressure fluid to the piston chamber, and opposed actuating surfaces on the valve intermittently subjected to pressure fluid for throwing the valve.

5. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid opening into the ends of the valve chamber, inlet passages leading from the end portions of the valve chamber to the end portions of the piston chamber, a valve in the valve chamber to control communication between the supply passages and the inlet passages and having a passage that constitutes a, continuation of one of the supply passages during the admission of pressure fluid to one end of the piston chamber and constitutes a 7 continuation-of another supply passage during the admission of pressure fluid to the other end of the piston chamber, and opposed actuating surfaces on the valve intermittently subjected to pressure fluid valved by the piston for throwing the valve, and opposed holding surfaces on the valve subjected to pressure fluid flowing to the inlet passages for holding the valve.

6. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the easing, opposed'supply passages for pressure fluid opening into the valve chamber, inlet passages of pressure fluid to the piston chamber, and opposed holding surfaces on the valve subjected to pressure fluid for holding the valve.

7. In a fluid actuated rock drill, the combination of a casinghaving a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid opening into the valve chamber, inlet passages leading from the valve chamber to the piston chamber, a valve in the valve chamber to control communication between the supply passages and the inlet passages and having a passage through which pressure fluid flows alternately in opposite directions for charging the ends of the piston chamber, and opposed holding surfaces on the valve adjacent the ends of the passage in the valve and being subjected to pressure fluid flowing from the supply passages to the inlet passages for holding the valve.

8. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, an annular valve chamber in the casing, opposed supply passages for: pressure fluid opening into the ends of the valve. chamber, inlet passages leading from the end portions of the valve chamber to the end portions of the piston chamber, an annular valve in the.- valve chamber to control communication between the supply passages and the inlet passages and having a passage that alternately constitutes a continuation of the supply passages during the admission of pressure fluid to the piston chamber and said passage in the valve being in constant communication with all the supply passages, and

means on the valve and in the valve chamber cooperating with each other to cut-oil communication between the supply passages and an inlet passage leading to one end portion of the piston chamber during the charging of the other end portion of the piston chamber.

9. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid opening into the valve chamber, inlet passages leading from the valve chamber to the piston chamber, a valve in the valve chamber to control communication between the supply passages and the inlet passages and acting to cut-off communication between the supply passages and one inlet passage and to simultaneously effect communication between all the supply passages and,

another inlet passage, and opposed areas on the valve intermittently subjected to medium compressed by the piston for throwing the valve.

10. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid 11. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston in the piston chamber, an exhaust port for the piston chamber, a valve chamber in the casing, opposed supply passages for pressure fluid opening into the valve chamber, inlet passages leading from the valve chamber to the piston chamber, a valve in the valve chamber to control communication between the supply passages and the inlet passages and acting to cut-off communication between the supply passages and one inlet passage and to simultaneously efiect communication between all the supply passages and another inlet passage, opposed actuating surfaces on the valve intermittently subjected to pressure fluid for throwing the valve, opposed areas on the valve subjected to medium compressed by the piston to assist in throwing the valve, and opposed holding surfaces on the valve subjected to the pressure fluid flowing from supply to the piston chamber for holding the valve.

WILLIAM A. MORRISON. 

